1. Field of the Invention
The invention relates generally to a device and method for programmably and automatically setting varying start and stop times of operation for a portable electronic timer device for providing, and cutting off, electrical power from a local AC power grid with respect to one or more external electrical devices connected to the electronic timer.
2. Description of the Related Art
As understood in the art, portable electronic timers may be used within homes or businesses to provide power to other electrical devices plugged into such a timer at certain selected times. Typically, such timers are electro-mechanical in design and are plugged into a power outlet within a home or business to turn on and off lights, or other electrical devices which are connected to the timer, for various reasons. For example, for a home or small business, a lighting device, such as a lamp, may be connected to such a timer so that the lamp is turned on or off at the same pre-selected time(s) each day for the convenience of the home or business owner. The owner may desire to save on utility bills by restricting use of the lighting device, or desire to avoid having to physically walk around the home or business to manually turn on and off lights, or to attempt to fool a potential burglar that the owner of the home or business is home at night by automatically turning on and off lights without being physically present.
As described above, such timers are typically electro-mechanical in design and have limited programmable functionality. Such timers typically include an exterior rotary dial which is rotated by a user in one direction to set the timer to the current time. Additionally, the rotary dial typically has imprinted thereon 24 equally spaced, intervals to indicate each of the 24 hours in a day. At the periphery of the rotary dial, for each of the 24 equally spaced intervals, there typically a plurality of physical holes to approximate 10 or 15 minute graduations for each of the 24 hours, depending on the number of holes for each hour increment on the rotary dial.
For such a rotary timer, one or more sets of mechanical pins can be inserted into any of the various physical holes to correspond to a start time (start time pin) and a stop time (stop time pin) for each set of pins, whereby the electro-mechanical timer will provide power from the home or business power grid to one or more electrical devices which are plugged into, or otherwise electrically connected to, an output of the electro-mechanical timer. The insertion of the set of mechanical pins into the rotary dial performs a function of “programming” the timer for a desired approximate start and stop time for correspondingly turning on and turning off a light or other electrical device. These “programmed” times, however, are fixed and are not variable from day to day. A spring-tensioned electrical switch disposed within the rotary dial contacts an end of the start pin (which provides electrical power to the output) at a first time and then, at a later time, contacts an end of the stop pin which has been inserted into a hole on the periphery of the rotary dial. After the desired stop and start times are set by a user via the insertion of the start and stop pins, the rotary dial is rotated by the user to set the current time, by aligning an arrow or other external indicator with a time value indicated on the rotary dial, and the timer is plugged into a wall outlet to provide electrical power to the timer. The rotary timer is then running and set.
Once electrical power is provided to the timer, the timer will then continuously rotate, very slowly, in either a clockwise or a counter-clockwise direction, depending on the design. When the end of the start pin, which has been previously inserted into the rotary dial by a user to program the timer for a start time, contacts the spring-tensioned electrical switch disposed within the rotary timer, power is provided from the power grid of the home or business to the electrical device which is plugged into the timer. Conversely, when the end of the stop pin, which has been previously inserted into the rotary dial by a user to program the timer for a stop time, contacts the spring-tensioned electrical switch disposed within the rotary timer, power is cut of from the power grid of the home or business to the electrical device which is plugged into the timer. Some such timers allow the use of two or more sets of start and stop pins to program the timer, but once set (unless there is a power failure) the timer will start and stop at the same time each day.
An obvious disadvantage of these types of rotary electro-mechanical timers is that all pre-selected start and stop times are, once set by a user via the insertion of the mechanical start and stop pins in the rotary dial, incapable of being changed (varied) unless the pins are physically pulled out by the user and reinserted into different holes to indicate a different mechanical programming of the timer. Thus, for example, a timer which has an inserted start pin which causes the timer to initiate the provision of electrical power to a lamp connected to the timer at 7:02 pm, and has an inserted stop pin which causes the timer to cut off the electrical power to the lamp at 10:32 pm, will (without an interruption of power to the timer itself) continuously perform the tuning on and the turning off of the lamp, on a daily basis, at the same times.
Any potential burglar on the outside of the home or business can easily monitor, on a daily basis, the on and off times of internal lighting for the home or business. Since the on and off times for the lamp will not vary day to day for the rotary electro-mechanical timer, the potential burglar may deduce that the occupant of the home or business is not home. Of course, the potential burglar may also look for other signs of occupancy, such as cars in the driveway, other lights in the home being used, or other obvious signs of human activity, before deducing that the home or business is ripe for a break-in.
However, many people who take a vacation, go on a business trip, or participate in any other activity which causes their home or business to be unoccupied for a period of days or weeks, typically use such an electro-mechanical rotary timer to attempt to fool any potential burglar, or nosey neighbor, that they are home and are not away, via the automatic turning on and off of a lamp in the home or business. Thus, they would be susceptible to a “casing” of their house by a potential burglar who will surely notice that a light is being turned on and off at the same time each day, and that no other signs of human activity appear at the house.
Another disadvantage of these types of rotary electro-mechanical timers is that pre-selected start and stop times are not capable of being precisely chosen. The start and stop times are not exactly prederminable, since the pre-manufactured holes physically arranged at the periphery of the rotary dial, into which the start and stop pins are inserted, may not align with any precise graduation of time designated on the rotary dial. For example, a hole may not aligns precisely with the designation of 1 PM or 1:15 PM, etc. and activation of the switch may actually occur 3-5 minutes (or more) away from the actual desire time of start or stop. Thus, for example, a start pin inserted into a hole near the designation “1 PM” may actually trigger the switch at 1:05 pm (or 12:55 PM) and not at precisely 1 PM. The same reasoning applies to any stop time for any stop pin.
An additional disadvantage is that such an electro-mechanical timer device cannot operate when there is a loss of electrical power being supplied to the device, which may occur during an electrical thunderstorm, nearby utility work, etc., while the home or business owner is away. Thus, if power is lost at any time while the owner is away the electro-mechanical timer cannot operate and the light will not turn on and off as desired. Furthermore, even if power is restored to the timer after several minutes (or worse, several hours or days) the timer will resume operation at the point of time that power is restored, but the times for turn-on and turn-off of the light previously set by the owner are now skewed by the time period of the power outage. Thus, for power outages of several hours or more, the timer will cause the light to turn on and off at times vastly different than those preselected by the owner and perhaps may occur during daylight hours instead of during the night, thereby allowing an potential burglar to easily discern that no lights are visible at night in the home or business.
Therefore, a need exists for an electronic timer which is easily programmable by a home occupier or business owner, which can be plugged into an electrical outlet of the home or business, and which can vary the start and stop times on a day to day basis for, respectfully, providing and cutting off electrical power from the power grid of the home or business via the timer in regard to a lamp or any other electrical device plugged into the timer.
Additionally, there is a need for an electronic timer that will not skew pre-selected “turn on” and “turn off” times by the amount of time during which AC power to the electronic timer is unavailable or insufficient.